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Brian Ellis
27th November 2013, 08:59
http://www.bbc.co.uk/news/magazine-25086097

Despite the economic and environmental cost at Chernobyl, I still believe that properly managed nuke electricity, with modern reactors is the only way to go in the energy debate.

dZeus
28th November 2013, 00:48
http://www.bbc.co.uk/news/magazine-25086097

Despite the economic and environmental cost at Chernobyl, I still believe that properly managed nuke electricity, with modern reactors is the only way to go in the energy debate.

yup, however, we need to do some introspection about how compatible properly managed is with human nature.

The stories about how Tepco managed its power plants (up to the Fukushima accident) are downright surreal, and I'm sure they were not unique with this type of behaviour.

I'd love to see figures of how many spent nuclear fuel rods are stored in the same building as the reactor for nuclear power plants all over the world (and the post-fukushima change in these figures). And the role of so-called pro-environment organizations like Greenpeace that systematically block transport of spent nuclear fuel rods from the reactor sites.

VJ
28th November 2013, 01:41
A professor of mine has an interesting opinion on this. He considers investments in wind turbines and solar energy a waste of money, and claims it would be better to go full ahead on researching nuclear fusion. He says that science is currently at the point where it is known that it will work, so we just have to make it work.
He says that the faster we crack that one, the better. Achieving that one 5 years earlier might do much more for the environment than messing around with other sources.

It is a bit an extreme view, but I can get the reasoning behind it.

Dr Mordrid
28th November 2013, 03:58
Fusion for power using Tokamak tech will always be just 10-15 year's away. There are a couple of interesting alternatives, but funding isn't as good as it should be. To rocket propulsion it's much closer and may be tested in space within a few years.

As for fission, there are reactor designs that arye far safer than Fukushima etc. , even passively safe, so they need toibe used in the near and middle terms.

Brian Ellis
28th November 2013, 06:37
The stories about how Tepco managed its power plants (up to the Fukushima accident) are downright surreal, and I'm sure they were not unique with this type of behaviour.

I'd love to see figures of how many spent nuclear fuel rods are stored in the same building as the reactor for nuclear power plants all over the world (and the post-fukushima change in these figures). And the role of so-called pro-environment organizations like Greenpeace that systematically block transport of spent nuclear fuel rods from the reactor sites.

I agree re Tepco. Unfortunately, ****youshima was a Generation 1c design (Chernobyl 1a) which should have been replaced by the time of the accident. It was designed to resist a M7 quake and, in fact, resisted an M9 with only minor damage. The designers at GE did not foresee a flood of sea water. The fact of having the emergency generators in a basement (the floor of which was below sea and aquifer levels) was the one major design flaw and Tepco cannot be blamed for that. If this flaw had not been there and the generators placed as in modern designs, the accident would never have happened. As for the cooling ponds being above the reactors, in a way, is logical, but not at all clever. It is interesting that emergency shut-down procedures were correctly well under way long before the tsunami arrived (generators started, control rods dropped in place, cooling water pumped into the reactors etc.). Tepco's "surrealism" was largedly the way they handled the affair after the event, but without any forward planning.

As for your last paragraph, I shudder to think how many Generation 1x reactors (>35 years old) are still in service. Even Switzerland has one (Mulhausen) of identical design to the Fukushima plant, cooled by a river flowing through steep-sided valleys (landslides possible, damming the river and suddenly ceding). The fuel rods are not stored there, but in Federal cooling ponds at Wuerenlingen (for all their reactors). The reactor was shut down within 24 hours, and the emergency generators had been moved to high ground less than 4 weeks after Fukushima. It will remain in service until, I think, 2020, despite many known problems. The national knee-jerk reaction to Fukushima, just one week after event, was a Federal Ordinance to close down all nukes by 2030, without having thought how to replace the 36% of the country's capacity.

As for blocking fuel supplies, Greenpeace should be treated as they were treated in Russia! They are not "so-called pro-environment organizations"; they are money-making fraudsters preying on the credulous.

Brian Ellis
28th November 2013, 07:53
A professor of mine has an interesting opinion on this. He considers investments in wind turbines and solar energy a waste of money, and claims it would be better to go full ahead on researching nuclear fusion. He says that science is currently at the point where it is known that it will work, so we just have to make it work.
He says that the faster we crack that one, the better. Achieving that one 5 years earlier might do much more for the environment than messing around with other sources.

It is a bit an extreme view, but I can get the reasoning behind it.

I agree with him re wind and, especially, solar (excepting solar hot water). I do not agree that we know it will work on a commercial scale and we won't know until the small scale ITER prototype produces results in ~2045. With my scientist's hat on, I say the concept of the hypothesis is interesting, if... When I put on my engineering hat, I can't understand how GW of plasma power in 5 second pulses can be converted to continuous thermal power.

Brian Ellis
28th November 2013, 08:17
Fusion for power using Tokamak tech will always be just 10-15 year's away. There are a couple of interesting alternatives, but funding isn't as good as it should be. To rocket propulsion it's much closer and may be tested in space within a few years.

As for fission, there are reactor designs that arye far safer than Fukushima etc. , even passively safe, so they need toibe used in the near and middle terms.

See my replies below.

I disagree re Tokamak, your 10-15 years are too optimistic. 25-30 years are more realistic, cf. ITER! :)

Even the 30 y.o. Generation 2n reactors were safer than the Generation 1n reactors still in service! :( Keeping with conventional U technology, the Generation 3a reactors currently on the market are considered to be as safe as possible with a mean time between catastrophic failure of the order of 10,000 years. As for thorium, there is a problem, Houston! It requires a fast breeder reactor to switch it to a useable isotope and every schoolkid knows that FBRs are the least stable of all reactors! :(

UtwigMU
28th November 2013, 10:58
I'd love to see figures of how many spent nuclear fuel rods are stored in the same building as the reactor for nuclear power plants all over the world (and the post-fukushima change in these figures). And the role of so-called pro-environment organizations like Greenpeace that systematically block transport of spent nuclear fuel rods from the reactor sites.


Since most of stores for spent fuel are in the planning stages and no one wants them near their town, most spent rods are in reactor buildings.

dZeus
28th November 2013, 11:21
Since most of stores for spent fuel are in the planning stages and no one wants them near their town, most spent rods are in reactor buildings.

I think spent nuclear fuel is also reprocessed, for example at the site in La Hague here in France. I'm not sure where the fraction of the fuel that cannot be re-used is stored.

UtwigMU
28th November 2013, 11:34
I think spent nuclear fuel is also reprocessed, for example at the site in La Hague here in France. I'm not sure where the fraction of the fuel that cannot be re-used is stored.

In our nuclear plant all nuclear waste (high (rods), medium and low (gloves, protective clothes) is stored at the nuclear plant. In Yugoslavia it was agreed that Slovenia gets the plant and Croatia gets the high radioactive waste. Now Croatia who own half of the plant and get half electricity don't want highly radioactive waste store and in Slovenia where local mayors reign supreme it's politically impossible to build a waste store. Thus all rods since 1980 are in the pools at the plant.

The local communities in Slovenia won't even allow for military range to operate (infantry and occasional artillery fire) which has been there since Maria Theresa in 1700s.

Another problem is that a lot of plants are pre Chernobyl since nuclear energy became unpopular. Austria has a nuclear plant built that was never put in commission because people voted so on referendum. When plants came for consideration again recently Fukushima happened. Thus it's hard to build new plants and existing 40y+ old ones are becoming less safe.

Brian Ellis
29th November 2013, 00:36
I think spent nuclear fuel is also reprocessed, for example at the site in La Hague here in France. I'm not sure where the fraction of the fuel that cannot be re-used is stored.

The recycling is the MOX process (Mixed OXides). This involves sending spent rods to La Hague or Sellafield. There, the contents are separated into mainly depleted U and Pu isotopes. Oxides of the two metals are mixed, in given proportions, and refilled into rods which are sent back for re-use (very simplified!). 96% of original rod contents are recycled.

Why is the process not used more?
1. Because only Generation 3 reactors can use PuO2 fuel which requires fast neutrons to maintain a chain reaction. Earlier reactors are too slow. Thus, only a small number of reactors in service can use recycled fuel
2. Because US Congress and President Carter enacted a bill banning the use of recycled fuel, so that no MOX-friendly reactors have been built in the USA, which has no Pu-handling facility, as a result. This stupid law has cost the US taxpayer and electricity consumer an arm, a leg and both cojones. All weapons-grade Pu past its sell-by date has to be sent to France in a convoy of 3 cargo vessels (only one contains the Pu) and an armed escort amidst the tightest security. The Pu is then used in Europe and Japan for MOX reactors. The risk of a transport/handling accident is not negligible.

I believe the 4% non-recyclable is mainly low-level depleted U without specific precautions required. It has other lighter metals in it and it is uneconomical to exploit.

Brian Ellis
29th November 2013, 00:56
Spent non-recyclable fuel rods are highly reactive and are kept in water for ~40 years under defined conditions, to moderate the neutron emissions and to keep them cold. After 40 years, their activity is medium-low and they can be handled. The cooling ponds were in ad hoc buildings in all 3 of the plants I've visited, 2 of them with tin roofs. Some are even outside. They seem to be in the general area where incineration and vitrification of low-level waste occurs.

Wulfman
1st December 2013, 05:43
Austria has a nuclear plant built that was never put in commission because people voted so on referendum. When plants came for consideration again recently Fukushima happened. .

I don't think we ever came close to reconsidering, at any point in time. The folly in Austria was really the fact that they built it first, and then asked the population shortly before putting the fuel rods (1978, even before Czernobyl!). The site seems to make good business in the security/emergency training market, since it is the only full-scale nuclear powerplant where you can enter the reactor room. So lots of SWAT teams kicking in doors, firemen rushing the building and engineers crawling throught the tunnels... :)

If you get a laugh out of those things: we spent about a billion on something that looks like a nuclear power plant, but is used as a photovoltaic site.

Mfg
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UtwigMU
1st December 2013, 08:52
Wulfman, long time no see. Are you still in UK or back to Austria (http://www.youtube.com/watch?v=St0kfFhMOio). I'm thinking of moving to Austria myself. :)